Preparation And Characterization Of High-performance Niobate Phosphors

Since the 21st century,rare earth luminescent materials have been widely used in social production and people’s life.In this paper,The niobate luminescent material represented by ZnNb₂O₆ are selected for their excellent optical properties and good physical properties.Therefore,ZnNb₂O₆ as the matrix of luminescent materials is of certain scientific value.At present,the rare earth doped silicate,aluminate,molybdate and other luminescent materials have been studied and perfected.In order to further explore the luminescent materials with high performance,the niobate represented by ZnNb₂O₆ of orthogonal crystal system was selected to study its luminescent function.The results show that the rare earth luminescent materials with ZnNb₂O₆ as the matrix are efficient and have excellent thermal stability.In this paper,the traditional high temperature solid phase method is used in the preparation of niobate luminescent materials.The phases of luminescent materials are analyzed by X-ray diffractometer.The excitation and emission spectra of luminescent materials were characterized by fluorescence spectrometer.The micromorphology of the luminescent material was characterized by SU-8010 scanning electron microscope.The absorption spectra of luminescent materials were measured by integrating spherical spectrophotometer.This paper focuses on the physical connotation of ZnNb₂O₆ luminescent materials in energy transfer and the realization of charge compensation.The research results of this paper are as follows:1.The structure of ZnNb₂O₆ crystal,Eu³⁺and its luminescent properties were studied,and the application of Eu³⁺as a fluorescent probe was briefly described.The ZnNb₂O₆crystal was used as the matrix to doping Eu³⁺.According to the excitation spectrum,there was a charge transfer zone of Eu³⁺→O^2-between 240 nm and 300 nm.From the excitation spectrum of 310 nm to 550 nm,it could be seen that the characteristic emission peaks all came from the f-f transition of Eu³⁺.The optimal doping concentration of Eu³⁺was 0.25mol,and the critical distance of concentration quenching was calculated.The symmetry of Eu³⁺in matrix lattice is determined by emission spectrum and the relationship between emission spectrum split and crystal field was studied.2.The effect of charge compensator on luminescent properties of luminescent materials was studied.The excitation and emission spectra of ZnNb₂O₆:Eu³⁺were studied.On this basis,the improvement of the luminescence performance of ZnNb₂O₆:Eu³⁺by charge compensator was studied.The results showed that the luminescence intensity of ZnNb₂O₆:Eu³⁺was nearly doubled when the concentration of Li⁺was 0.25mol.Finally,the absorption spectrum and its optical bandgap and thermal stability of enhanced red phosphors Zn_0.5Nb₂O₆:0.25Eu³⁺,0.25Li⁺was studied.Through the analysis of color coordinates,it is found that the color coordinates of Zn_0.5Nb₂O₆:0.25Eu³⁺,0.25Li⁺are close to the color coordinates of the international lighting association standard for orange-red light.3.The physical implications of Sm³⁺and Eu³⁺co-doping ZnNb₂O₆ in terms of energy transfer were studied.In this paper,the single-doped Eu³⁺and its single-doped Sm³⁺luminous properties of ZnNb₂O₆ crystals were studied respectively.The results showed that the optimal doping concentration of single-doped Eu³⁺was 0.25 mol,and the optimal doping concentration of single-doped Sm³⁺was 0.01 mol.Then,the concentration of Sm³⁺was fixed at 0.01 mol,and the emission spectra of the co-doped two ions were observed by constantly changing the concentration of Eu³⁺.According to the co-doped emission spectra,the characteristic emission peak of Sm³⁺was continuously weakened with the continuous increase of Eu³⁺concentration.In addition,according to the concentration quenching critical distance formula proposed by Blasse,the energy transfer mode after co-doping was calculated to be the electric multi-pole interaction under the resonant energy transfer mode,and then the linear relationship of R² was further obtained to be the electric dipole-electric dipole interaction.In order to further explore the physical connotation of energy transfer,to test the fluorescence lifetime,the results found that with increasing Eu³⁺concentration,fluorescence lifetime is constantly falling,so that the total energy transfer phenomenon happened in doped system,and the last to calculate the energy transfer efficiency,the results show that the energy transfer efficiency up to 85.39%,therefore,Zn_0.74Nb₂O₆:0.25Eu³⁺,0.01 Sm³⁺is a kind of efficient and new type red phosphors.